B12 too high?

My B12 is high too. Check the level of B12 in your multivitamin if you take one. One a Day Vitamins have over 1,000% of the recommended daily allowance. I asked my pharmacist if there was a brand with less B12. He told me not to worry…that too much B12 is not dangerous in a multivitamin because we don’t absorb more than 1% of it. I am very confused.

Did you get a Folate lab as well? Maybe Homocysteine too ?

I don't have the MTHFR variant that raises B12 so my B12 is normal, but the Folate has been on the moon and it is very hard to get down. Methylene tetrahydrofolate reductase (MTHFR) is when your body builds up essentially toxic levels of folic acid (man-made synthetic form) plus in some they get a B12 component too, but you lack enough of the enzyme function to convert it to the active and natural form Folate (Vitamin B9 a.k.a. methylfolate). Don't take non methyl versions of either, no cyanocobalmin or folic acid.

If you go to a hematologist, they will say B vitamins in excess are excreted. Just problem is they are not if you have these genes that let the build up happen, sometimes after decades of too high you may have issues, GI issues, low stomach acid, thyroid, autoimmune various issues, etc. Sounds like you have the thyroid issue already, I had thyroid cancer so at least you don't have that.
https://www.amymyersmd.com/article/mthfr-mutation

I have to drink LiquidIV due to POTS and my VitB12 was almost 2000. For me the Dr said it's from consuming the extra vitamins in those types of drinks. Certain drinks have added vitamins and can add up quickly, the levels can sneak up on you.

Hi there- I agree with the others… Usually a high B12 level is from a supplement. But it’s also not usually considered dangerous because your body eventually dumps the excess B12 (that said, you can have toxicity from other B vitamins, just not B12). Do you have symptoms you and your doctor are concerned about?

Someone mentioned Liquid IV (the electrolyte supplement). I also have POTS and drank this daily, and it pushed my B12 up high. I was told
That was fine. I did have to stop it because it pushed my B6 level too high, which was a problem because it causes and was exacerbating my existing neuropathy, so I had to stop it.

Are you taking any similar supplements that might be sneakily pushing up your level?

Are there any symptoms of high B12?

Yes, there can be symptoms of high B12 levels in some people. If my level rises above 700 pg/mL I experience insomnia. It took me years to figure out what the culprit was. Fortunately, my multivitamin has just 100 mcg of B12 that keeps my level between 650-700 and lets me sleep soundly.

Just because there is no established upper limit for B12 it doesn’t mean there are no adverse effects. Repeated dogma dictates we will pass the excess out in urine. That’s not entirely true.

If you subscribe to ConsumerLab.com you will see there are many well researched and published side-effects of high B12 levels including:

1. Higher incidence of heart attack, stroke, death in diabetics.
2. Poorer disease-free and survival rates of those undergoing chemotherapy.
3. 77% increased relative risk of having colorectal cancer for those taking 500 mcg of B12.
4. 85% increased chance of early death above a level of 455 pg/mL
5. There are more adverse effects cited as well.
https://www.consumerlab.com/reviews/review-best-b-vitamins-and-complexes-energy-b6-b12-biotin-niacin-folic-acid/bvitamins/
Unless people have a B12 deficiency to correct it’s probably best to get our levels measured, stay with a low-dose B12 supplement if needed, and not let our levels get too high.

That’s really concerning to me because I was deficient, treated but continued to have symptoms….now being treated again with high dose…and just got new symptoms. My neurologist said not to look at my post treatment number, but my deficiency number. He said it could take months to years to restore.

So what was your before treatment and after treatment B12 levels?

Before treatment was 172. After treatment 700.
The 700 was in Sept 2023. He didn’t take a new one….yet. He ordered the intrinsic antibody test and a few others.

Well, you’re now in the normal range according to typical lab values. Every lab has a slightly different range but a 200-900 range is typical. My doc says he like his patients around 500-600.

I’m guessing here, but I suspect your neurologist gave you high-dose B12 injections or oral supplements to get your levels up. He now may likely suggest a lower dose oral supplement to help you maintain your level so your levels don’t drop.